1. Field of the Invention
The present invention relates to a method for manufacturing agglomerates of sintered pellets, and more particularly, to a method for manufacturing agglomerates of sintered pellets as material for a blast furnace.
2. Description of Related Art
Agglomerates of sintered pellets are used for material for a blast furnace. Fine iron ore containing 40 or more wt. % fine material for pellets, flux and return fines generated at the step of manufacturing agglomerates of sintered pellets are mixed with each other. Water is added to the fine iron ore, flux and return fines. A mixture thus obtained is pelletized into green pellets of 4 to 10 mm in particle size by a disk pelletizer. The green pellets thus obtained and powdery coke are supplied into a drum mixer. The surfaces of the green pellets are coated with the powdery coke in the drum mixer. Agglomerates of sintered pellets are manufactured by sintering green pellets coated with the powdery coke in a travelling endless grate type sintering machine. A method for coating the surfaces of the green pellets is disclosed in Japanese Laid Open Patent Publication No. 149333/88. The powdery coke, with which the surfaces of the green pellets are coated, is produced by crushing small size coke pieces generated in a quenching apparatus and a screening apparatus at the step of production of lumpish coke for a blast furnace, by means of a rod mill.
However, although powdery coke of small particle size is used for coating the surfaces of the green pellets, there is a problem in that powdery coke of comparatively large particle size remains unused. When the powdery coke of coarse grain size is used as fuel for a blast furnace, gas permeability in the blast furnace is poor.